Aromatic Polymer Composition for Use in a Camera Module

ABSTRACT

A polymer composition that contains an aromatic polymer in combination with a tribological formulation is provided. The polymer composition may exhibit a low degree of surface friction that minimizes the extent to which a skin layer is peeled off during use of a part containing the composition (e.g., in a camera module). For example, the polymer composition may exhibit a dynamic coefficient of friction of about 1.0 or less and/or a wear depth may be about 500 micrometers or less as determined in accordance with VDA 230-206:2007.

RELATED APPLICATIONS

The present application claims priority to U.S. Application Serial Nos.62/594,603 (filed on Dec. 5, 2017) and 62/746,757 (filed on Oct. 17,2018), which are incorporated herein in their entirety by referencethereto.

BACKGROUND OF THE INVENTION

Camera modules (or components) are often employed in mobile phones,laptop computers, digital cameras, digital video cameras, etc. Examplesinclude, for instance, compact camera modules that include a carriermounted to a base, digital camera shutter modules, components of digitalcameras, cameras in games, medical cameras, surveillance cameras, etc.Such camera modules have become more complex and now tend to includemultiple moving parts. In some cases, for example, two compact cameramodule assemblies can be mounted within a single module to improvepicture quality (“dual camera” modules). In other cases, an array ofcompact camera modules can be employed. Regardless of the particulardesign, liquid crystalline polymers are often used during manufacturingdue to their highly oriented crystal structure, which allows thepolymers to be readily molded into very small and complex parts.Unfortunately, however, the highly oriented structure also makes liquidcrystalline polymers susceptible to wear. Namely, one or more skinlayers of the polymer tend to be peeled off from the part during use,which can lead to a poor appearance and/or performance.

As such, a need exists for a polymer composition that can be readilyemployed in camera modules.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a polymercomposition is disclosed that comprises at least one aromatic polymer(e.g., thermotropic liquid crystalline polymer) and a tribologicalformulation in an amount from about 1 to about 20 parts by weight per100 parts by weight of the aromatic polymer. The tribologicalformulation contains a fluorinated additive and a siloxane polymerhaving a weight average molecular weight of about 100,000 grams per moleor more. The weight ratio of the fluorinated additive to the siloxanepolymer is from about 0.5 to about 12.

In accordance with yet another embodiment of the present invention, acamera module is disclosed that comprises a base on which is mounted acarrier assembly. The base, carrier assembly, or both comprise a moldedpart. The molded part contains a polymer composition that includes atleast one thermotropic liquid crystalline polymer and a tribologicalformulation. The polymer composition exhibits a dynamic coefficient offriction of about 0.4 or less as determined in accordance with VDA230-206:2007.

Other features and aspects of the present invention are set forth ingreater detail below.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention, including thebest mode thereof to one skilled in the art, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures, in which:

FIGS. 1-2 are perspective and front views of a compact camera module(“CCM”) that may be formed in accordance with one embodiment of thepresent invention.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentinvention.

Generally speaking, the present invention is directed to a polymercomposition that contains an aromatic polymer in combination with atribological formulation. By selectively controlling the nature of thesecomponents and their relative concentration, the present inventor hasdiscovered that the resulting polymer composition can achieve a lowdegree of surface friction that minimizes the extent to which a skinlayer is peeled off during use of a part containing the composition(e.g., in a camera module). For example, the polymer composition mayexhibit a dynamic coefficient of friction of about 1.0 or less, in someembodiments about 0.4 or less, in some embodiments about 0.35 or less,and in some embodiments, from about 0.1 to about 0.3, as determined inaccordance with VDA 230-206:2007. Likewise, the wear depth may be about500 micrometers or less, in some embodiments about 200 micrometers orless, in some embodiments about 100 micrometers or less, and in someembodiments, from about 10 to about 70 micrometers, as determined inaccordance with VDA 230-206:2007.

Conventionally, it was believed that parts having such a low frictionsurface would not also possess sufficiently good mechanical properties.Contrary to conventional thought, however, the composition of thepresent invention has been found to possess excellent mechanicalproperties. For example, the composition may exhibit a Charpy unnotchedimpact strength greater than about 20 kJ/m², in some embodiments fromabout 25 to about 100 kJ/m², and in some embodiments, from about 30 toabout 80 kJ/m², measured at 23° C. according to ISO Test No. 179-1:2010(technically equivalent to ASTM D256-10e1). The composition may alsoexhibit a Charpy notched impact strength greater than about 0.5 kJ/m²,in some embodiments from about 1 to about 20 kJ/m², and in someembodiments, from about 5 to about 15 kJ/m², measured at 23° C.according to ISO Test No. 179-1:2010 (technically equivalent to ASTMD256-10e1). The tensile and flexural mechanical properties are alsogood. For example, the composition may exhibit a tensile strength offrom about 20 to about 500 MPa, in some embodiments from about 50 toabout 400 MPa, and in some embodiments, from about 60 to about 350 MPa;tensile break strain of about 1% or more, in some embodiments from about2% to about 15%, and in some embodiments, from about 3% to about 10%;and/or tensile modulus of from about 4,000 MPa to about 20,000 MPa, insome embodiments from about 5,000 MPa to about 18,000 MPa, and in someembodiments, from about 6,000 MPa to about 12,000 MPa. The tensileproperties may be determined in accordance with ISO Test No. 527:2012(technically equivalent to ASTM D638-14) at 23° C. The composition mayalso exhibit a flexural strength of from about 20 to about 500 MPa, insome embodiments from about 50 to about 400 MPa, and in someembodiments, from about 80 to about 350 MPa and/or a flexural modulus offrom about 4,000 MPa to about 20,000 MPa, in some embodiments from about5,000 MPa to about 18,000 MPa, and in some embodiments, from about 6,000MPa to about 15,000 MPa. The flexural properties may be determined inaccordance with ISO Test No. 178:2010 (technically equivalent to ASTMD790-10) at 23° C. The molded part may also exhibit a deflectiontemperature under load (DTUL) of about 180° C. or more, and in someembodiments, from about 190° C. to about 280° C., as measured accordingto ASTM D648-07 (technically equivalent to ISO Test No. 75-2:2013) at aspecified load of 1.8 MPa. The Rockwell hardness of the part may also beabout 25 or more, some embodiments about 30 or more, and in someembodiments, from about 35 to about 80, as determined in accordance withASTM D785-08 (Scale M).

In addition, the composition can also exhibit excellent antistaticbehavior, particularly when an antistatic filler is included within thepolymer composition as discussed above. Such antistatic behavior can becharacterized by a relatively low surface and/or volume resistivity asdetermined in accordance with IEC 60093. For example, the compositionmay exhibit a surface resistivity of about 1×10¹⁵ ohms or less, in someembodiments about 1×10¹⁴ ohms or less, in some embodiments from about1×10¹⁰ ohms to about 9×10¹³ ohms, and in some embodiments, from about1×10¹¹ to about 1×10¹³ ohms. Likewise, the molded part may also exhibita volume resistivity of about 1×10¹⁵ ohm-m or less, in some embodimentsfrom about 1×10⁹ ohm-m to about 9×10¹⁴ ohm-m, and in some embodiments,from about 1×10¹⁰ to about 5×10¹⁴ ohm-m. Of course, such antistaticbehavior is by no means required. For example, in some embodiments, thecomposition may exhibit a relatively high surface resistivity, such asabout 1×10¹⁵ ohms or more, in some embodiments about 1×10¹⁶ ohms ormore, in some embodiments from about 1×10¹⁷ ohms to about 9×10³⁰ ohms,and in some embodiments, from about 1×10¹⁸ to about 1×10²⁶ ohms.

Various embodiments of the present invention will now be described inmore detail.

I. Polymer Composition

A. Aromatic Polymer

Aromatic polymers typically constitute from about 20 wt. % to about 70wt. %, in some embodiments from about 30 wt. % to about 65 wt. %, and insome embodiments, from about 40 wt. % to about 60 wt. % of the polymercomposition. The aromatic polymers are generally considered “highperformance” polymers in that they have a relatively high glasstransition temperature and/or high melting temperature depending on theparticular nature of the polymer. Such high performance polymers canthus provide a substantial degree of heat resistance to the resultingpolymer composition. For example, the aromatic polymer may have a glasstransition temperature of about 100° C. or more, in some embodimentsabout 120° C. or more, in some embodiments from about 140° C. to about350° C., and in some embodiments, from about 150° C. to about 320° C.The aromatic polymer may also have a melting temperature of about 200°C. or more, in some embodiments from about 220° C. to about 400° C., andin some embodiments, from about 240° C. to about 380° C. The glasstransition and melting temperatures may be determined as is well knownin the art using differential scanning calorimetry (“DSC”), such asdetermined by ISO Test No. 11357-2:2013 (glass transition) and11357-3:2011 (melting).

The aromatic polymer can be substantially amorphous, semi-crystalline,or crystalline in nature. One example of a suitable semi-crystallinearomatic polymer, for instance, is an aromatic polyamide. Particularlysuitable aromatic polyamides are those having a relatively high meltingtemperature, such as about 200° C. or more, in some embodiments about220° C. or more, and in some embodiments, from about 240° C. to about320° C., as determined using differential scanning calorimetry accordingto ISO Test No. 11357. The glass transition temperature of aromaticpolyamides is likewise generally from about 110° C. to about 160° C.

Aromatic polyamides typically contain repeating units held together byamide linkages (NH—CO) and are synthesized through the polycondensationof dicarboxylic acids (e.g., aromatic dicarboxylic acids), diamines(e.g., aliphatic diamines), etc. For example, the aromatic polyamide maycontain aromatic repeating units derived from an aromatic dicarboxylicacid, such as terephthalic acid, isophthalic acid,2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid,1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxy-diacetic acid,1,3-phenylenedioxy-diacetic acid, diphenic acid, 4,4′-oxydibenzoic acid,diphenylmethane-4,4′-dicarboxylic acid,diphenylsulfone-4,4′-dicarboxylic acid, 4,4′-biphenyldicarboxylic acid,etc., as well as combinations thereof. Terephthalic acid is particularlysuitable. Of course, it should also be understood that other types ofacid units may also be employed, such as aliphatic dicarboxylic acidunits, polyfunctional carboxylic acid units, etc. The aromatic polyamidemay also contain aliphatic repeating units derived from an aliphaticdiamine, which typically has from 4 to 14 carbon atoms. Examples of suchdiamines include linear aliphatic alkylenediamines, such as1,4-tetramethylenediamine, 1,6-hexanediamine, 1,7-heptanediamine,1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine,1,11-undecanediamine, 1,12-dodecanediamine, etc.; branched aliphaticalkylenediamines, such as 2-methyl-1,5-pentanediamine, 3-methyl-1,5pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine,2,4,4-trimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine,2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, etc.; as well ascombinations thereof. Repeating units derived from 1,9-nonanediamineand/or 2-methyl-1,8-octanediamine are particularly suitable. Of course,other diamine units may also be employed, such as alicyclic diamines,aromatic diamines, etc.

Particularly suitable polyamides may include poly(nonamethyleneterephthalamide) (PA9T), poly(nonamethyleneterephthalamide/nonamethylene decanediamide) (PA9T/910),poly(nonamethylene terephthalamide/nonamethylene dodecanediamide)(PA9T/912), poly(nonamethylene terephthalamide/11-aminoundecanamide)(PA9T/11), poly(nonamethylene terephthalamide/12-aminododecanamide)(PA9T/12), poly(decamethylene terephthalamide/11-aminoundecanamide) (PA10T/11), poly(decamethylene terephthalamide/12-aminododecanamide)(PA10T/12), poly(decamethylene terephthalamide/decamethylenedecanediamide) (PA10T/1010), poly(decamethyleneterephthalamide/decamethylene dodecanediamide) (PA10T/1012),poly(decamethylene terephlhalamide/tetramethylene hexanediamide)(PA10T/46), poly(decamethylene terephthalamide/caprolactam) (PA10T/6),poly(decamethylene terephthalamide/hexamethylene hexanediamide)(PA10T/66), poly(dodecamethylene lerephthalamide/dodecamelhylenedodecanediarnide) (PA12T/1212), poly(dodecamethyleneterephthalamide/caprolactam) (PA12T/6), poly(dodecamethyleneterephthalamide/hexamethylene hexanediamide) (PA12T/66), and so forth.Yet other examples of suitable aromatic polyamides are described in U.S.Pat. No. 8,324,307 to Harder, et al.

Another suitable semi-crystalline aromatic polymer that may be employedin the present invention is a polyaryletherketone. Polyaryletherketonesare semi-crystalline polymers with a relatively high meltingtemperature, such as from about 300° C. to about 400° C., in someembodiments from about 310° C. to about 390° C., and in someembodiments, from about 330° C. to about 380° C. The glass transitiontemperature may likewise be from about 110° C. to about 200° C.Particularly suitable polyaryletherketones are those that primarilyinclude phenyl moieties in conjunction with ketone and/or ethermoieties. Examples of such polymers include polyetheretherketone(“PEEK”), polyetherketone (“PEK”), polyetherketoneketone (“PEKK”),polyetherketoneetherketoneketone (“PEKEKK”), polyetheretherketoneketone(“PEEKK”),polyether-diphenyl-ether-ether-diphenyl-ether-phenyl-ketone-phenyl,etc., as well as blends and copolymers thereof.

As indicated above, substantially amorphous polymers may also beemployed in the polymer composition that lack a distinct melting pointtemperature. Suitable amorphous polymers may include, for instance,polyphenylene oxide (“PPO”), aromatic polycarbonates, aromaticpolyetherimides, etc. Aromatic polycarbonates, for instance, typicallyhave a glass transition temperature of from about 130° C. to about 160°C. and contain aromatic repeating units derived from one or morearomatic diols. Particularly suitable aromatic diols are bisphenols,such as gem-bisphenols in which two phenols groups are attached to asingle carbon atom of a bivalent connecting radical. Examples of suchbisphenols may include, for instance, such as4,4′-isopropylidenediphenol (“bisphenol A”), 4,4′-ethylidenediphenol,4,4′-(4-chloro-a-methylbenzylidene)diphenol,4,4′cyclohexylidenediphenol, 4,4 (cyclohexylmethylene)diphenol, etc., aswell as combinations thereof. The aromatic diol may be reacted with aphosgene. For example, the phosgene may be a carbonyl chloride havingthe formula C(O)Cl₂. An alternative route to the synthesis of anaromatic polycarbonate may involve the transesterification of thearomatic diol (e.g., bisphenol) with a diphenyl carbonate.

In addition to the polymers referenced above, crystalline polymers mayalso be employed in the polymer composition. Particularly suitable areliquid crystalline polymers, which have a high degree of crystallinitythat enables them to effectively fill the small spaces of a mold. Liquidcrystalline polymers are generally classified as “thermotropic” to theextent that they can possess a rod-like structure and exhibit acrystalline behavior in their molten state (e.g., thermotropic nematicstate). The polymers have a relatively high melting temperature, such asfrom about 250° C. to about 400° C., in some embodiments from about 280°C. to about 390° C., and in some embodiments, from about 300° C. toabout 380° C. Such polymers may be formed from one or more types ofrepeating units as is known in the art. A liquid crystalline polymermay, for example, contain one or more aromatic ester repeating units,typically in an amount of from about 60 mol. % to about 99.9 mol. %, insome embodiments from about 70 mol. % to about 99.5 mol. %, and in someembodiments, from about 80 mol. % to about 99 mol. % of the polymer. Thearomatic ester repeating units may be generally represented by thefollowing Formula (I):

wherein,

-   -   ring B is a substituted or unsubstituted 6-membered aryl group        (e.g., 1,4-phenylene or 1,3-phenylene), a substituted or        unsubstituted 6-membered aryl group fused to a substituted or        unsubstituted 5- or 6-membered aryl group (e.g.,        2,6-naphthalene), or a substituted or unsubstituted 6-membered        aryl group linked to a substituted or unsubstituted 5- or        6-membered aryl group (e.g., 4,4-biphenylene); and    -   Y₁ and Y₂ are independently O, C(O), NH, C(O)HN, or NHC(O).

Typically, at least one of Y₁ and Y₂ are C(O). Examples of such aromaticester repeating units may include, for instance, aromatic dicarboxylicrepeating units (Y₁ and Y₂ in Formula I are C(O)), aromatichydroxycarboxylic repeating units (Y₁ is O and Y₂ is C(O) in Formula I),as well as various combinations thereof.

Aromatic dicarboxylic repeating units, for instance, may be employedthat are derived from aromatic dicarboxylic acids, such as terephthalicacid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4′-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid,2,7-naphthalenedicarboxylic acid, 4,4′-dicarboxybiphenyl,bis(4-carboxyphenyl)ether, bis(4-carboxyphenyl)butane,bis(4-carboxyphenyl)ethane, bis(3-carboxyphenyl)ether,bis(3-carboxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryl andhalogen substituents thereof, and combinations thereof. Particularlysuitable aromatic dicarboxylic acids may include, for instance,terephthalic acid (“TA”), isophthalic acid (“IA”), and2,6-naphthalenedicarboxylic acid (“NDA”). When employed, repeating unitsderived from aromatic dicarboxylic acids (e.g., IA, TA, and/or NDA)typically constitute from about 5 mol. % to about 60 mol. %, in someembodiments from about 10 mol. % to about 55 mol. %, and in someembodiments, from about 15 mol. % to about 50% of the polymer.

Aromatic hydroxycarboxylic repeating units may also be employed that arederived from aromatic hydroxycarboxylic acids, such as, 4-hydroxybenzoicacid; 4-hydroxy-4′-biphenylcarboxylic acid; 2-hydroxy-6-naphthoic acid;2-hydroxy-5-naphthoic acid; 3-hydroxy-2-naphthoic acid;2-hydroxy-3-naphthoic acid; 4′-hydroxyphenyl-4-benzoic acid;3′-hydroxyphenyl-4-benzoic acid; 4′-hydroxyphenyl-3-benzoic acid, etc.,as well as alkyl, alkoxy, aryl and halogen substituents thereof, andcombination thereof. Particularly suitable aromatic hydroxycarboxylicacids are 4-hydroxybenzoic acid (“NBA”) and 6-hydroxy-2-naphthoic acid(“HNA”). When employed, repeating units derived from hydroxycarboxylicacids (e.g., HBA and/or HNA) typically constitute from about 10 mol. %to about 85 mol. %, in some embodiments from about 20 mol. % to about 80mol. %, and in some embodiments, from about 25 mol. % to about 75% ofthe polymer.

Other repeating units may also be employed in the polymer. In certainembodiments, for instance, repeating units may be employed that arederived from aromatic diols, such as hydroquinone, resorcinol,2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,1,6-dihydroxynaphthalene, 4,4′-dihydroxybiphenyl (or 4,4′-biphenol),3,3′-dihydroxybiphenyl, 3,4′-dihydroxybiphenyl, 4,4′-dihydroxybiphenylether, bis(4-hydroxyphenyl)ethane, etc., as well as alkyl, alkoxy, aryland halogen substituents thereof, and combinations thereof. Particularlysuitable aromatic diols may include, for instance, hydroquinone (“HQ”)and 4,4′-biphenol (“BP”). When employed, repeating units derived fromaromatic diols (e.g., HQ and/or BP) typically constitute from about 1mol. % to about 30 mol. %, in some embodiments from about 2 mol. % toabout 25 mol. %, and in some embodiments, from about 5 mol. % to about20% of the polymer. Repeating units may also be employed, such as thosederived from aromatic amides (e.g., acetaminophen (“APAP”)) and/oraromatic amines (e.g., 4-aminophenol (“AP”), 3-aminophenol,1,4-phenylenediamine, 1,3-phenylenediamine, etc.). When employed,repeating units derived from aromatic amides (e.g., APAP) and/oraromatic amines (e.g., AP) typically constitute from about 0.1 mol. % toabout 20 mol. %, in some embodiments from about 0.5 mol. % to about 15mol. %, and in some embodiments, from about 1 mol. % to about 10% of thepolymer. It should also be understood that various other monomericrepeating units may be incorporated into the polymer. For instance, incertain embodiments, the polymer may contain one or more repeating unitsderived from non-aromatic monomers, such as aliphatic or cycloaliphatichydroxycarboxylic acids, dicarboxylic acids, diols, amides, amines, etc.Of course, in other embodiments, the polymer may be “wholly aromatic” inthat it lacks repeating units derived from non-aromatic (e.g., aliphaticor cycloaliphatic) monomers.

Although not necessarily required, the liquid crystalline polymer may bea “low naphthenic” polymer to the extent that it contains a minimalcontent of repeating units derived from naphthenic hydroxycarboxylicacids and naphthenic dicarboxylic acids, such asnaphthalene-2,6-dicarboxylic acid (“NDA”), 6-hydroxy-2-naphthoic acid(“HNA”), or combinations thereof. That is, the total amount of repeatingunits derived from naphthenic hydroxycarboxylic and/or dicarboxylicacids (e.g., NDA, HNA, or a combination of HNA and NDA) is typically nomore than 30 mol. %, in some embodiments no more than about 15 mol. %,in some embodiments no more than about 10 mol. %, in some embodiments nomore than about 8 mol. %, and in some embodiments, from 0 mol. % toabout 5 mol. % of the polymer (e.g., 0 mol. %). Despite the absence of ahigh level of conventional naphthenic acids, it is believed that theresulting “low naphthenic” polymers are still capable of exhibiting goodthermal and mechanical properties.

In one particular embodiment, the liquid crystalline polymer may beformed from repeating units derived from 4-hydroxybenzoic acid (“NBA”)and terephthalic acid (“TA”) and/or isophthalic acid (“IA”), as well asvarious other optional constituents. The repeating units derived from4-hydroxybenzoic acid (“HBA”) may constitute from about 10 mol. % toabout 80 mol. %, in some embodiments from about 30 mol. % to about 75mol. %, and in some embodiments, from about 45 mol. % to about 70% ofthe polymer. The repeating units derived from terephthalic acid (“TA”)and/or isophthalic acid (“IA”) may likewise constitute from about 5 mol.% to about 40 mol. %, in some embodiments from about 10 mol. % to about35 mol. %, and in some embodiments, from about 15 mol. % to about 35% ofthe polymer. Repeating units may also be employed that are derived from4,4′-biphenol (“BP”) and/or hydroquinone (“HQ”) in an amount from about1 mol. % to about 30 mol. %, in some embodiments from about 2 mol. % toabout 25 mol. %, and in some embodiments, from about 5 mol. % to about20% of the polymer. Other possible repeating units may include thosederived from 6-hydroxy-2-naphthoic acid (“HNA”),2,6-naphthalenedicarboxylic acid (“NDA”), and/or acetaminophen (“APAP”).In certain embodiments, for example, repeating units derived from HNA,NDA, and/or APAP may each constitute from about 1 mol. % to about 35mol. %, in some embodiments from about 2 mol. % to about 30 mol. %, andin some embodiments, from about 3 mol. % to about 25 mol. % whenemployed.

B. Tribological Formulation

A tribological formulation is also employed in the polymer composition,typically in an amount of from about 1 to about 30 parts, in someembodiments from about 2 to about 15 parts, and in some embodiments,from about 4 to about 12 parts per 100 parts of aromatic polymer(s)employed in the polymer composition. For example, the tribologicalformulation may constitute from about 1 wt. % to about 30 wt. %, in someembodiments from about 2 wt. % to about 25 wt. %, and in someembodiments, from about 4 wt. % to about 10 wt. % of the polymercomposition.

The tribological formulation generally contains a siloxane polymer thatimproves internal lubrication and that also helps to bolster the wearand friction properties of the composition encountering another surface.Such siloxane polymers typically constitute from about 0.1 to about 20parts, in some embodiments from about 0.4 to about 10 parts, and in someembodiments, from about 0.5 to about 5 parts per 100 parts of aromaticpolymer(s) employed in the composition. Any of a variety of siloxanepolymers may generally be employed in the tribological formulation. Thesiloxane polymer may, for instance, encompass any polymer, co-polymer oroligomer that includes siloxane units in the backbone having theformula:

R_(r)SiO_((4-r/2))

wherein

-   -   R is independently hydrogen or substituted or unsubstituted        hydrocarbon radicals, and    -   r is 0, 1, 2 or 3.

Some examples of suitable radicals R include, for instance, alkyl, aryl,alkylaryl, alkenyl or alkynyl, or cycloalkyl groups, optionallysubstituted, and which may be interrupted by heteroatoms, i.e., maycontain heteroatom(s) in the carbon chains or rings. Suitable alkylradicals, may include, for instance, methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl andtert-pentyl radicals, hexyl radicals (e.g., n-hexyl), heptyl radicals(e.g., n-heptyl), octyl radicals (e.g., n-octyl), isooctyl radicals(e.g., 2,2,4-trimethylpentyl radical), nonyl radicals (e.g., n-nonyl),decyl radicals (e.g., n-decyl), dodecyl radicals (e.g., n-dodecyl),octadecyl radicals (e.g., n-octadecyl), and so forth. Likewise, suitablecycloalkyl radicals may include cyclopentyl, cyclohexyl cycloheptylradicals, methylcyclohexyl radicals, and so forth; suitable arylradicals may include phenyl, biphenyl, naphthyl, anthryl, andphenanthryl radicals; suitable alkylaryl radicals may include o-, m- orp-tolyl radicals, xylyl radicals, ethylphenyl radicals, and so forth;and suitable alkenyl or alkynyl radicals may include vinyl, 1-propenyl,1-butenyl, 1-pentenyl, 5-hexenyl, butadienyl, hexadienyl, cyclopentenyl,cyclopentadienyl, cyclohexenyl, ethynyl, propargyl 1-propynyl, and soforth. Examples of substituted hydrocarbon radicals are halogenatedalkyl radicals (e.g., 3-chloropropyl, 3,3,3-trifluoropropyl, andperfluorohexylethyl) and halogenated aryl radicals (e.g., p-chlorophenyland p-chlorobenzyl). In one particular embodiment, the siloxane polymerincludes alkyl radicals (e.g., methyl radicals) bonded to at least 70mol % of the Si atoms and optionally vinyl and/or phenyl radicals bondedto from 0.001 to 30 mol % of the Si atoms. The siloxane polymer is alsopreferably composed predominantly of diorganosiloxane units. The endgroups of the polyorganosiloxanes may be trialkylsiloxy groups, inparticular the trimethylsiloxy radical or the dimethylvinylsiloxyradical. However, it is also possible for one or more of these alkylgroups to have been replaced by hydroxy groups or alkoxy groups, such asmethoxy or ethoxy radicals. Particularly suitable examples of thesiloxane polymer include, for instance, dimethylpolysiloxane,phenylmethylpolysiloxane, vinylmethylpolysiloxane, andtrifluoropropylpolysiloxane.

The siloxane polymer may also include a reactive functionality on atleast a portion of the siloxane monomer units of the polymer, such asone or more of vinyl groups, hydroxyl groups, hydrides, isocyanategroups, epoxy groups, acid groups, halogen atoms, alkoxy groups (e.g.,methoxy, ethoxy and propoxy), acyloxy groups (e.g., acetoxy andoctanoyloxy), ketoximate groups (e.g., dimethylketoxime, methylketoximeand methylethylketoxime), amino groups(e.g., dimethylamino, diethylaminoand butylamino), amido groups (e.g., N-methylacetamide andN-ethylacetamide), acid amido groups, amino-oxy groups, mercapto groups,alkenyloxy groups (e.g., vinyloxy, isopropenyloxy, and1-ethyl-2-methylvinyloxy), alkoxyalkoxy groups (e.g., methoxyethoxy,ethoxyethoxy and methoxypropoxy), aminoxy groups (e.g., dimethylaminoxyand diethylaminoxy), mercapto groups, etc.

Regardless of its particular structure, the siloxane polymer typicallyhas a relatively high molecular weight, which reduces the likelihoodthat it migrates or diffuses to the surface of the polymer compositionand thus further minimizes the likelihood of phase separation. Forinstance, the siloxane polymer typically has a weight average molecularweight of about 100,000 grams per mole or more, in some embodimentsabout 200,000 grams per mole or more, and in some embodiments, fromabout 500,000 grams per mole to about 2,000,000 grams per mole. Thesiloxane polymer may also have a relative high kinematic viscosity, suchas about 10,000 centistokes or more, in some embodiments about 30,000centistokes or more, and in some embodiments, from about 50,000 to about500,000 centistokes.

If desired, silica particles (e.g., fumed silica) may also be employedin combination with the siloxane polymer to help improve its ability tobe dispersed within the composition. Such silica particles may, forinstance, have a particle size of from about 5 nanometers to about 50nanometers, a surface area of from about 50 square meters per gram(m²/g) to about 600 m²/g, and/or a density of from about 160 kilogramper cubic meter (kg/m³) to about 190 kg/m³. When employed, the silicaparticles typically constitute from about 1 to about 100 parts, and insome some embodiments, from about 20 to about 60 parts by weight basedon 100 parts by weight of the siloxane polymer. In one embodiment, thesilica particles can be combined with the siloxane polymer prior toaddition of this mixture to the polymer composition. For instance amixture including an ultrahigh molecular weight polydimethylsiloxane andfumed silica can be incorporated in the polymer composition. Such apre-formed mixture is available as Genioplast® Pellet S from WackerChemie, AG.

The tribological formulation may also contain other components that canhelp the resulting polymer composition to achieve a good combination oflow friction and good wear resistance. In one embodiment, for instance,the tribological formulation may employ a fluorinated additive incombination with the siloxane polymer. Without intending to be limitedby theory, it is believed that the fluorinated additive can, among otherthings, improve the processing of the composition, such as by providingbetter mold filling, internal lubrication, mold release, etc. Whenemployed, the weight ratio of the fluorinated additive to the siloxanepolymer is typically from about 0.5 to about 12, in some embodimentsfrom about 0.8 to about 10, and in some embodiments, from about 1 toabout 6. For example, the fluorinated additive may constitute from about0.1 to about 20 parts, in some embodiments from about 0.5 to about 15parts, and in some embodiments, from about 1 to about 10 parts per 100parts of aromatic polymer(s) employed in the composition.

In certain embodiments, the fluorinated additive may include afluoropolymer, which contains a hydrocarbon backbone polymer in whichsome or all of the hydrogen atoms are substituted with fluorine atoms.The backbone polymer may polyolefinic and formed fromfluorine-substituted, unsaturated olefin monomers. The fluoropolymer canbe a homopolymer of such fluorine-substituted monomers or a copolymer offluorine-substituted monomers or mixtures of fluorine-substitutedmonomers and non-fluorine-substituted monomers. Along with fluorineatoms, the fluoropolymer can also be substituted with other halogenatoms, such as chlorine and bromine atoms. Representative monomerssuitable for forming fluoropolymers for use in this invention aretetrafluoroethylene, vinylidene fluoride, hexafluoropropylene,chlorotrifluoroethylene, perfluoroethylvinyl ether, perfluoromethylvinylether, perfluoropropylvinyl ether, etc., as well as mixtures thereof.Specific examples of suitable fluoropolymers includepolytetrafluoroethylene, perfluoroalkylvinyl ether,poly(tetrafluoroethylene-co-perfluoroalkyvinylether), fluorinatedethylene-propylene copolymer, ethylene-tetrafluoroethylene copolymer,polyvinylidene fluoride, polychlorotrifluoroethylene, etc., as well asmixtures thereof.

The fluorinated additive may contain only the fluoropolymer, or it mayalso include other ingredients, such as those that aid in its ability tobe uniformly dispersed within the polymer composition. In oneembodiment, for example, the fluorinated additive may include afluoropolymer in combination with a plurality of carrier particles. Insuch embodiments, for instance, the fluoropolymer may be coated onto thecarrier particles. Silicate particles are particularly suitable for thispurpose, such as talc (Mg₃Si₄O₁₀(OH)₂), halloysite (Al₂Si₂O₅(OH)₄),kaolinite (Al₂Si₂O₅(OH)₄), illite ((K, H₃O)(Al, Mg, Fe)₂(Si,Al)₄O₁₀[(OH)₂,(H₂O)]), montmorillonite (Na, Ca)_(0.33)(Al,Mg)₂Si₄O₁₀(OH)₂·nH₂O), vermiculite ((MgFe, Al)₃(Al, Si)₄O₁₀(OH)₂·4H₂O),palygorskite ((Mg, Al)₂Si₄O₁₀(OH)·4(H₂O)), pyrophyllite(Al₂Si₄O₁₀(OH)₂), calcium silicate, aluminum silicate, mica,diatomaceous earth, wollastonite, and so forth. Mica, for instance, maybe a particularly suitable mineral for use in the present invention.There are several chemically distinct mica species with considerablevariance in geologic occurrence, but all have essentially the samecrystal structure. As used herein, the term “mica” is meant togenerically include any of these species, such as muscovite(KAl₂(AlSi₃)O₁₀(OH)₂), biotite (K(Mg,Fe)₃(AlSi₃)O₁₀(OH)₂), phlogopite(KMg₃(AlSi₃)O₁₀(OH)₂), lepidolite (K(Li,Al)₂₋₃(AlSi₃)O₁₀(OH)₂),glauconite (K, Na)(Al, Mg, Fe)₂(Si, Al)₄O₁₀(OH)₂), etc., as well ascombinations thereof. The carrier particles may have an average particlesize of from about 5 to about 50 micrometers, and in some embodiments,from about 10 to 20 micrometers. If desired, the carrier particles mayalso be in the shape of plate-like particles in that the ratio of itsmajor axis to thickness is 2 or more.

C. Other Optional Components

i. Inorganic Filler

If desired, an inorganic filler may be employed for improving certainproperties of the polymer composition. For example, the present inventorhas discovered that the use of inorganic fillers with a certain hardnessvalue can improve the mechanical strength, adhesive strength, andsurface smoothness of a part containing the composition. The resultingpolymer composition may also be able to achieve less delamination of thepolymer skin layer, which enables it to be uniquely suited for verysmall parts. The inorganic filler may be employed in the polymercomposition in an amount of from about 10 to about 95 parts, in someembodiments from about 20 to about 90 parts, and in some embodiments,from about 50 to about 85 parts by weight per 100 parts of the aromaticpolymer(s) employed in the polymer composition. For instance, theinorganic filler may constitute from about 10 wt. % to about 70 wt. %,in some embodiments from about 20 wt. % to about 60 wt. %, and in someembodiments, from about 30 wt. % to about 60 wt. % of the polymercomposition.

The nature of the inorganic filler may vary, such as particles, fibers,etc. In certain embodiments, for instance, inorganic filler particlesmay be employed having a certain hardness value to help improve thesurface properties of the composition. For instance, the hardness valuesmay be about 2.5 or more, in some embodiments about 3.0 or more, in someembodiments from about 3.0 to about 11.0, in some embodiments from about3.5 to about 11.0, and in some embodiments, from about 4.5 to about 6.5based on the Mohs hardness scale. Examples of such particles mayinclude, for instance, carbonates, such as calcium carbonate (CaCO₃,Mohs hardness of 3.0) or a copper carbonate hydroxide (Cu₂CO3(OH)₂, Mohshardness of 4.0); fluorides, such as calcium fluoride (CaFl₂, Mohshardness of 4.0); phosphates, such as calcium pyrophosphate ((Ca₂P₂O₇,Mohs hardness of 5.0), anhydrous dicalcium phosphate (CaHPO₄, Mohshardness of 3.5), or hydrated aluminum phosphate (AlPO₄·2H2O, Mohshardness of 4.5); silicates, such as silica (SiO₂, Mohs hardness of6.0), potassium aluminum silicate (KAISi₃O₈, Mohs hardness of 6), orcopper silicate (CuSiO₃·H₂O, Mohs hardness of 5.0); borates, such ascalcium borosilicate hydroxide (Ca₂B₅SiO₉(OH)₅, Mohs hardness of 3.5);alumina (AlO₂, Mohs hardness of 10.0); sulfates, such as calcium sulfate(CaSO₄, Mohs hardness of 3.5) or barium sulfate (BaSO₄, Mohs hardness offrom 3 to 3.5); and so forth, as well as combinations thereof. Whenemployed, the inorganic particles typically have a median size (e.g.,diameter) of from about 0.1 to about 35 micrometers, in some embodimentsfrom about 2 to about 20 micrometers, in some embodiments from about 3to about 15 micrometers, and in some embodiments, from about 7 to about12 micrometers, such as determined using laser diffraction techniques inaccordance with ISO 13320:2009 (e.g., with a Horiba LA-960 particle sizedistribution analyzer). The filler inorganic particles may also have anarrow size distribution. That is, at least about 70% by volume of theparticles, in some embodiments at least about 80% by volume of theparticles, and in some embodiments, at least about 90% by volume of theparticles may have a size within the ranges noted above.

The inorganic filler may also be fibers derived from a material havingthe desired hardness value. Particularly suitable fibers for thispurpose include those derived from minerals, including silicates, suchas neosilicates, sorosilicates, inosilicates (e.g., calciuminosilicates, such as wollastonite; calcium magnesium inosilicates, suchas tremolite; calcium magnesium iron inosilicates, such as actinolite;magnesium iron inosilicates, such as anthophyllite; etc.),phyllosilicates (e.g., aluminum phyllosilicates, such as palygorskite),tectosilicates, etc.; sulfates, such as calcium sulfates (e.g.,dehydrated or anhydrous gypsum); mineral wools (e.g., rock or slagwool); and so forth. Particularly suitable are fibers derived frominosilicates, such as wollastonite (Mohs hardness of 4.5 to 5.0), whichare commercially available from Nyco Minerals under the tradedesignation NYGLOS® (e.g., NYGLOS® 4W or NYGLOS® 8). When employed, themineral fibers may have a median width (e.g., diameter) of from about0.1 to about 35 micrometers, in some embodiments from about 2 to about20 micrometers, in some embodiments from about 3 to about 15micrometers, and in some embodiments, from about 7 to about 12micrometers, such as determined using laser diffraction techniques inaccordance with ISO 13320:2009 (e.g., with a Horiba LA-960 particle sizedistribution analyzer). The mineral fibers may also have a narrow sizedistribution. That is, at least about 70% by volume of the fibers, insome embodiments at least about 80% by volume of the fibers, and in someembodiments, at least about 90% by volume of the fibers may have a sizewithin the ranges noted above. The mineral fibers may also have anaspect ratio of from about 1 to about 50, in some embodiments from about2 to about 20, and in some embodiments, from about 4 to about 15. Thevolume average length of such mineral fibers may, for example, rangefrom about 1 to about 200 micrometers, in some embodiments from about 2to about 150 micrometers, in some embodiments from about 5 to about 100micrometers, and in some embodiments, from about 10 to about 50micrometers.

ii. Impact Modifier

If desired, an impact modifier may also be employed in the polymercomposition to help improve the impact strength and flexibility of thepolymer composition. In fact, the present inventor has discovered thatthe impact modifier can actually make the surface of a molded partsmoother and minimize the likelihood that a skin layer is peeledtherefrom during use. When employed, the impact modifier typicallyconstitutes from about 0.1 to about 20 parts, in some embodiments fromabout 0.2 to about 10 parts, and in some embodiments, from about 0.5 toabout 5 parts by weight per 100 parts of the aromatic polymer(s)employed in the polymer composition. For instance, the impact modifiermay constitute from about 0.1 wt. % to about 10 wt. %, in someembodiments from about 0.2 wt. % to about 8 wt. %, and in someembodiments, from about 0.5 wt. % to about 4 wt. % of the polymercomposition.

One particularly suitable type of impact modifier may include, forinstance, an olefin copolymer that is “epoxy-functionalized” in that itcontains, on average, two or more epoxy functional groups per molecule.The copolymer generally contains an olefinic monomeric unit that isderived from one or more α-olefins. Examples of such monomers include,for instance, linear and/or branched α-olefins having from 2 to 20carbon atoms and typically from 2 to 8 carbon atoms. Specific examplesinclude ethylene, propylene, 1-butene; 3-methyl-1-butene;3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl,ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl orpropyl substituents; 1-heptene with one or more methyl, ethyl or propylsubstituents; 1-octene with one or more methyl, ethyl or propylsubstituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin monomers areethylene and propylene. The copolymer may also contain anepoxy-functional monomeric unit. One example of such a unit is anepoxy-functional (meth)acrylic monomeric component. As used herein, theterm “(meth)acrylic” includes acrylic and methacrylic monomers, as wellas salts or esters thereof, such as acrylate and methacrylate monomers.For example, suitable epoxy-functional (meth)acrylic monomers mayinclude, but are not limited to, those containing 1,2-epoxy groups, suchas glycidyl acrylate and glycidyl methacrylate. Other suitableepoxy-functional monomers include allyl glycidyl ether, glycidylethacrylate, and glycidyl itoconate. Other suitable monomers may also beemployed to help achieve the desired molecular weight.

Of course, the copolymer may also contain other monomeric units as isknown in the art. For example, another suitable monomer may include a(meth)acrylic monomer that is not epoxy-functional. Examples of such(meth)acrylic monomers may include methyl acrylate, ethyl acrylate,n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, s-butylacrylate, i-butyl acrylate, t-butyl acrylate, n-amyl acrylate, i-amylacrylate, isobornyl acrylate, n-hexyl acrylate, 2-ethylbutyl acrylate,2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate,methylcyclohexyl acrylate, cyclopentyl acrylate, cyclohexyl acrylate,methyl methacrylate, ethyl methacrylate, 2-hydroxyethyl methacrylate,n-propyl methacrylate, n-butyl methacrylate, i-propyl methacrylate,i-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, i-amylmethacrylate, s-butyl-methacrylate, t-butyl methacrylate, 2-ethylbutylmethacrylate, methylcyclohexyl methacrylate, cinnamyl methacrylate,crotyl methacrylate, cyclohexyl methacrylate, cyclopentyl methacrylate,2-ethoxyethyl methacrylate, isobornyl methacrylate, etc., as well ascombinations thereof. In one particular embodiment, for example, thecopolymer may be a terpolymer formed from an epoxy-functional(meth)acrylic monomeric component, α-olefin monomeric component, andnon-epoxy functional (meth)acrylic monomeric component. The copolymermay, for instance, be poly(ethylene-co-butylacrylate-co-glycidylmethacrylate), which has the following structure:

wherein, x, y, and z are 1 or greater.

The relative portion of the monomeric component(s) may be selected toachieve a balance between epoxy-reactivity and melt flow rate. Moreparticularly, high epoxy monomer contents can result in good reactivitywith the matrix polymer, but too high of a content may reduce the meltflow rate to such an extent that the copolymer adversely impacts themelt strength of the polymer blend. Thus, in most embodiments, theepoxy-functional (meth)acrylic monomer(s) constitute from about 1 wt. %to about 20 wt. %, in some embodiments from about 2 wt. % to about 15wt. %, and in some embodiments, from about 3 wt. % to about 10 wt. % ofthe copolymer. The α-olefin monomer(s) may likewise constitute fromabout 55 wt. % to about 95 wt. %, in some embodiments from about 60 wt.% to about 90 wt. %, and in some embodiments, from about 65 wt. % toabout 85 wt. % of the copolymer. When employed, other monomericcomponents (e.g., non-epoxy functional (meth)acrylic monomers) mayconstitute from about 5 wt. % to about 35 wt. %, in some embodimentsfrom about 8 wt. % to about 30 wt. %, and in some embodiments, fromabout 10 wt. % to about 25 wt. % of the copolymer. The result melt flowrate is typically from about 1 to about 30 grams per 10 minutes (“g/10min”), in some embodiments from about 2 to about 20 g/10 min, and insome embodiments, from about 3 to about 15 g/10 min, as determined inaccordance with ASTM D1238-13 at a load of 2.16 kg and temperature of190° C.

One example of a suitable epoxy-functionalized copolymer that may beused in the present invention is commercially available from Arkemaunder the name LOTADER® AX8840. LOTADER® AX8840, for instance, has amelt flow rate of 5 g/10 min and has a glycidyl methacrylate monomercontent of 8 wt. %. Another suitable copolymer is commercially availablefrom DuPont under the name ELVALOY® PTW, which is a terpolymer ofethylene, butyl acrylate, and glycidyl methacrylate and has a melt flowrate of 12 g/10 min and a glycidyl methacrylate monomer content of 4 wt.% to 5 wt. %.

iii. Antistatic Filler

An antistatic filler may also be employed in the polymer composition tohelp reduce the tendency to create a static electric charge during amolding operation, transportation, collection, assembly, etc. Suchfillers, when employed, typically constitute from about 0.1 to about 20parts, in some embodiments from about 0.2 to about 10 parts, and in someembodiments, from about 0.5 to about 5 parts by weight per 100 parts ofthe aromatic polymer(s) employed in the polymer composition. Forinstance, the antistatic filler may constitute from about 0.1 wt. % toabout 10 wt. %, in some embodiments from about 0.2 wt. % to about 8 wt.%, and in some embodiments, from about 0.5 wt. % to about 4 wt. % of thepolymer composition.

Any of a variety of antistatic fillers may generally be employed in thepolymer composition to help improve its antistatic characteristics.Examples of suitable antistatic fillers may include, for instance, metalparticles (e.g., aluminum flakes), metal fibers, carbon particles (e.g.,graphite, expanded graphite, grapheme, carbon black, graphitized carbonblack, etc.), carbon nanotubes, carbon fibers, and so forth. Carbonfibers and carbon particles (e.g., graphite) are particularly suitable.When employed, suitable carbon fibers may include pitch-based carbon(e.g., tar pitch), polyacrylonitrile-based carbon, metal-coated carbon,etc. Desirably, the carbon fibers have a high purity in that theypossess a relatively high carbon content, such as a carbon content ofabout 85 wt. % or more, in some embodiments about 90 wt. % or more, andin some embodiments, about 93 wt. % or more. For instance, the carboncontent can be at least about 94% wt., such as at least about 95% wt.,such as at least about 96% wt., such at least about 97% wt., such aseven at least about 98% wt. The carbon purity is generally less than 100wt. %, such as less than about 99 wt. %. The density of the carbonfibers is typically from about 0.5 to about 3.0 g/cm³, in someembodiments from about 1.0 to about 2.5 g/cm³, and in some embodiments,from about 1.5 to about 2.0 g/cm³.

In one embodiment, the carbon fibers are incorporated into the matrixwith minimal fiber breakage. The volume average length of the fibersafter molding can generally be from about 0.1 mm to about 1 mm even whenusing a fiber having an initial length of about 3 mm. The average lengthand distribution of the carbon fibers can also be selectively controlledin the final polymer composition to achieve a better connection andelectrical pathway within the liquid crystalline polymer matrix. Theaverage diameter of the fibers can be from about 0.5 to about 30micrometers, in some embodiments from about 1 to about 20 micrometers,and in some embodiments, from about 3 to about 15 micrometers.

To improve dispersion within the polymer matrix, the carbon fibers maybe at least partially coated with a sizing agent that increases thecompatibility of the carbon fibers with the liquid crystalline polymer.The sizing agent may be stable so that it does not thermally degrade attemperatures at which the liquid crystalline polymer is molded. In oneembodiment, the sizing agent may include a polymer, such as an aromaticpolymer. For instance, the aromatic polymer may have a thermaldecomposition temperature of greater than about 300° C., such as greaterthan about 350° C., such as greater than about 400° C. As used herein,the thermal decomposition temperature of a material is the temperatureat which the material losses 5% of its mass during thermogravimetericanalysis as determined in accordance with ASTM Test E 1131 (or ISO Test11358). The sizing agent can also have a relatively high glasstransition temperature. For instance, the glass transition temperatureof the sizing agent can be greater than about 300° C., such as greaterthan about 350° C., such as greater than about 400° C. Particularexamples of sizing agents include polyimide polymers, aromatic polyesterpolymers including wholly aromatic polyester polymers, and hightemperature epoxy polymers. In one embodiment, the sizing agent mayinclude a liquid crystalline polymer. The sizing agent can be present onthe fibers in an amount of at least about 0.1% wt., such as in an amountof at least 0.2% wt., such as in an amount of at least about 0.1% wt.The sizing agent is generally present in an amount less than about 5%wt., such as in an amount of less than about 3% wt.

Another suitable antistatic filler is an ionic liquid. One benefit ofsuch a material is that, in addition to being an antistatic agent, theionic liquid can also exist in liquid form during melt processing, whichallows it to be more uniformly blended within the polymer matrix. Thisimproves electrical connectivity and thereby enhances the ability of thecomposition to rapidly dissipate static electric charges from itssurface.

The ionic liquid is generally a salt that has a low enough meltingtemperature so that it can be in the form of a liquid when meltprocessed with the liquid crystalline polymer. For example, the meltingtemperature of the ionic liquid may be about 400° C. or less, in someembodiments about 350° C. or less, in some embodiments from about 1° C.to about 100° C., and in some embodiments, from about 5° C. to about 50°C. The salt contains a cationic species and counterion. The cationicspecies contains a compound having at least one heteroatom (e.g.,nitrogen or phosphorous) as a “cationic center.” Examples of suchheteroatomic compounds include, for instance, quaternary oniums havingthe following structures:

-   -   wherein, R¹, R², R³, R⁴, R⁵, R⁶, R⁷, and R⁸ are independently        selected from the group consisting of hydrogen; substituted or        unsubstituted C₁-C₁₀ alkyl groups (e.g., methyl, ethyl,        n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,        n-pentyl, etc.); substituted or unsubstituted C₃-C₁₄ cycloalkyl        groups (e.g., adamantyl, cyclopropyl, cyclobutyl, cyclopentyl,        cyclooctyl, cyclohexenyl, etc.); substituted or unsubstituted        C₁-C₁₀ alkenyl groups (e.g., ethylene, propylene,        2-methypropylene, pentylene, etc.); substituted or unsubstituted        C₂-C₁₀ alkynyl groups (e.g., ethynyl, propynyl, etc.);        substituted or unsubstituted C₁-C₁₀ alkoxy groups (e.g.,        methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy,        sec-butoxy, n-pentoxy, etc.); substituted or unsubstituted        acyloxy groups (e.g., methacryloxy, methacryloxyethyl, etc.);        substituted or unsubstituted aryl groups (e.g., phenyl);        substituted or unsubstituted heteroaryl groups (e.g., pyridyl,        furanyl, thienyl, thiazolyl, isothiazolyl, triazolyl,        imidazolyl, isoxazolyl, pyrrolyl, pyrazolyl, pyridazinyl,        pyrimidinyl, quinolyl, etc.); and so forth. In one particular        embodiment, for example, the cationic species may be an ammonium        compound having the structure N⁺R¹R²R³R⁴, wherein R¹, R², and/or        R³ are independently a C₁-C₆ alkyl (e.g., methyl, ethyl, butyl,        etc.) and R⁴ is hydrogen or a C₁-C₄ alkyl group (e.g., methyl or        ethyl). For example, the cationic component may be        tri-butylmethylammonium, wherein R¹, R², and R³ are butyl and R⁴        is methyl.

Suitable counterions for the cationic species may include, for example,halogens (e.g., chloride, bromide, iodide, etc.); sulfates or sulfonates(e.g., methyl sulfate, ethyl sulfate, butyl sulfate, hexyl sulfate,octyl sulfate, hydrogen sulfate, methane sulfonate, dodecylbenzenesulfonate, dodecylsulfate, trifluoromethane sulfonate,heptadecafluorooctanesulfonate, sodium dodecylethoxysulfate, etc.);sulfosuccinates; amides (e.g., dicyanamide); imides (e.g.,bis(pentafluoroethyl-sulfonyl)imide, bis(trifluoromethylsulfonyl)imide,bis(trifluoromethyl)imide, etc.); borates (e.g., tetrafluoroborate,tetracyanoborate, bis[oxalato]borate, bis[salicylato]borate, etc.);phosphates or phosphinates (e.g., hexafluorophosphate, diethylphosphate,bis(pentafluoroethyl)phosphinate,tris(pentafluoroethyl)-trifluorophosphate,tris(nonafluorobutyl)trifluorophosphate, etc.); antimonates (e.g.,hexafluoroantimonate); aluminates (e.g., tetrachloroaluminate); fattyacid carboxylates (e.g., oleate, isostearate, pentadecafluorooctanoate,etc.); cyanates; acetates; and so forth, as well as combinations of anyof the foregoing. To help improve compatibility with the liquidcrystalline polymer, it may be desired to select a counterion that isgenerally hydrophobic in nature, such as imides, fatty acidcarboxylates, etc. Particularly suitable hydrophobic counterions mayinclude, for instance, bis(pentafluoroethylsulfonyl)imide,bis(trifluoromethylsulfonyl)imide, and bis(trifluoromethyl)imide.

iv. Other Additives

A wide variety of additional additives can also be included in thepolymer composition, such as lubricants, thermally conductive fillers,pigments, antioxidants, stabilizers, surfactants, waxes, flameretardants, anti-drip additives, and other materials added to enhanceproperties and processability. Lubricants, for example, may be employedin the polymer composition that are capable of withstanding theprocessing conditions of the liquid crystalline polymer withoutsubstantial decomposition. Examples of such lubricants include fattyacids esters, the salts thereof, esters, fatty acid amides, organicphosphate esters, and hydrocarbon waxes of the type commonly used aslubricants in the processing of engineering plastic materials, includingmixtures thereof. Suitable fatty acids typically have a backbone carbonchain of from about 12 to about 60 carbon atoms, such as myristic acid,palmitic acid, stearic acid, arachic acid, montanic acid, octadecinicacid, parinric acid, and so forth. Suitable esters include fatty acidesters, fatty alcohol esters, wax esters, glycerol esters, glycol estersand complex esters. Fatty acid amides include fatty primary amides,fatty secondary amides, methylene and ethylene bisamides andalkanolamides such as, for example, palmitic acid amide, stearic acidamide, oleic acid amide, N,N′-ethylenebisstearamide and so forth. Alsosuitable are the metal salts of fatty acids such as calcium stearate,zinc stearate, magnesium stearate, and so forth; hydrocarbon waxes,including paraffin waxes, polyolefin and oxidized polyolefin waxes, andmicrocrystalline waxes. Particularly suitable lubricants are acids,salts, or amides of stearic acid, such as pentaerythritol tetrastearate,calcium stearate, or N,N′-ethylenebisstearamide. When employed, thelubricant(s) typically constitute from about 0.05 wt. % to about 1.5 wt.%, and in some embodiments, from about 0.1 wt. % to about 0.5 wt. % (byweight) of the polymer composition.

Of course, one beneficial aspect of the present invention is that goodmechanical properties may be achieved without adversely impacting thedimensional stability of the resulting part. To help ensure that thisdimensional stability is maintained, it is generally desirable that thepolymer composition remains substantially free of conventional fibrousfillers, such as glass fibers. Thus, if employed at all, such fiberstypically constitute no more than about 10 wt. %, in some embodiments nomore than about 5 wt. %, and in some embodiments, from about 0.001 wt. %to about 3 wt. % of the polymer composition.

II. Formation

The aromatic polymer, tribological formulation, and other optionaladditives may be melt processed or blended together. The components maybe supplied separately or in combination to an extruder that includes atleast one screw rotatably mounted and received within a barrel (e.g.,cylindrical barrel) and may define a feed section and a melting sectionlocated downstream from the feed section along the length of the screw.The extruder may be a single screw or twin screw extruder. The speed ofthe screw may be selected to achieve the desired residence time, shearrate, melt processing temperature, etc. For example, the screw speed mayrange from about 50 to about 800 revolutions per minute (“rpm”), in someembodiments from about 70 to about 150 rpm, and in some embodiments,from about 80 to about 120 rpm. The apparent shear rate during meltblending may also range from about 100 seconds⁻¹ to about 10,000seconds-1, in some embodiments from about 500 seconds⁻¹ to about 5000seconds-1, and in some embodiments, from about 800 seconds⁻¹ to about1200 seconds-1. The apparent shear rate is equal to 4Q/πR³, where Q isthe volumetric flow rate (“m³/s”) of the polymer melt and R is theradius (“m”) of the capillary (e.g., extruder die) through which themelted polymer flows.

Regardless of the particular manner in which it is formed, the presentinventor has discovered that the resulting polymer composition canpossess excellent thermal properties. For example, the melt viscosity ofthe polymer composition may be low enough so that it can readily flowinto the cavity of a mold having small dimensions. In one particularembodiment, the polymer composition may have a melt viscosity of fromabout 1 to about 200 Pa-s, in some embodiments from about 5 to about 180Pa-s, in some embodiments from about 10 to about 150 Pa-s, and in someembodiments, from about 60 to about 120 Pa-s, determined at a shear rateof 1000 seconds-1. Melt viscosity may be determined in accordance withISO Test No. 11443:2005 at a temperature that is 15° C. higher than themelting temperature of the composition (e.g., 350° C.).

III. Shaped Parts

Shaped parts may be formed from the polymer composition using a varietyof different techniques. Suitable techniques may include, for instance,injection molding, low-pressure injection molding, extrusion compressionmolding, gas injection molding, foam injection molding, low-pressure gasinjection molding, low-pressure foam injection molding, gas extrusioncompression molding, foam extrusion compression molding, extrusionmolding, foam extrusion molding, compression molding, foam compressionmolding, gas compression molding, etc. For example, an injection moldingsystem may be employed that includes a mold within which the polymercomposition may be injected. The time inside the injector may becontrolled and optimized so that polymer matrix is not pre-solidified.When the cycle time is reached and the barrel is full for discharge, apiston may be used to inject the composition to the mold cavity.Compression molding systems may also be employed. As with injectionmolding, the shaping of the polymer composition into the desired articlealso occurs within a mold. The composition may be placed into thecompression mold using any known technique, such as by being picked upby an automated robot arm. The temperature of the mold may be maintainedat or above the solidification temperature of the polymer matrix for adesired time period to allow for solidification. The molded product maythen be solidified by bringing it to a temperature below that of themelting temperature. The resulting product may be de-molded. The cycletime for each molding process may be adjusted to suit the polymermatrix, to achieve sufficient bonding, and to enhance overall processproductivity.

Due to its high fluidity, relatively thin shaped parts (e.g., injectionmolded parts) can be readily formed therefrom. For example, such partsmay have a thickness of about 10 millimeters or less, in someembodiments about 5 millimeters or less, and in some embodiments, fromabout 0.2 to about 4 millimeters (e.g., 0.3 or 3 millimeters). Whenforming an injection molded part, for instance, a relatively high“spiral flow length” can be achieved. The term “spiral flow length”generally refers to the length reached by the flow of the composition ina spiral flow channel when it is injected at constant injectiontemperature and injection pressure from a central gate of a mold inwhich the spiral flow channel is formed. The spiral flow length may, forinstance, be about 15 millimeter or more, in some embodiments about 20millimeters or more, in some embodiments about 22 millimeters or more,and in some embodiments, from about 25 to about 80 millimeters, asdetermined in accordance with ASTM D3121-09 at a barrel temperature of230° C., molding temperature of 40° C. to 60° C., and a maximuminjection pressure of 860 bar.

The polymer composition can also remain dimensionally stable when shapedinto a part, and thus exhibit a relatively low degree of warpage. Thedegree of warpage may be characterized by low “flatness values” asdetermined by the test described in more detail below. Moreparticularly, the polymer composition may exhibit a flatness value ofabout 1 millimeter or less, in some embodiments about 0.8 millimeters orless, and in some embodiments, from about 0.1 to about 0.7 millimeters.The composition may also maintain such a low warpage even after beingconditioned at high temperatures and humidity levels (e.g., 85° C. and85% relative humidity) for a substantial period of time (e.g., 72hours). For example, after being conditioned at 85° C./85% relativehumidity for 72 hours, the polymer composition may still exhibit aflatness value of about 2 millimeters or less, in some embodiments about1.5 millimeters or less, and in some embodiments, from about 0.1 toabout 1.2 millimeters.

A wide variety of types of parts may also be formed from the polymercomposition of the present invention. For example, the polymercomposition can be employed in lighting assemblies, battery systems,sensors and electronic components, portable electronic devices such assmart phones, MP3 players, mobile phones, computers, televisions,automotive parts, etc. In one particular embodiment, the polymercomposition may be employed in a camera module, such as those commonlyemployed in wireless communication devices (e.g., cellular telephone).For example, the camera module may employ a base, carrier assemblymounted on the base, a cover mounted on the carrier assembly, etc. Thebase may have a thickness of about 500 micrometers or less, in someembodiments from about 10 to about 450 micrometers, and in someembodiments, from about 20 to about 400 micrometers. Likewise, thecarrier assembly may have a wall thickness of about 500 micrometers orless, in some embodiments from about 10 to about 450 micrometers, and insome embodiments, from about 20 to about 400 micrometers.

One particularly suitable camera module is shown in FIGS. 1-2 . Asshown, a camera module 500 contains a carrier assembly 504 that overliesa base 506. The base 506, in turn, overlies an optional main board 508.Due to their relatively thin nature, the base 506 and/or main board 508are particularly suited to be molded from the polymer composition of thepresent invention. The carrier assembly 504 may have any of a variety ofconfigurations as is known in the art. In one embodiment, for example,the carrier assembly 504 may contain a hollow barrel that houses one ormore lenses 604, which are in communication with an image sensor 602positioned on the main board 508 and controlled by a circuit 601. Thebarrel may have any of a variety of shapes, such as rectangular,cylindrical, etc. In certain embodiments, the barrel may be formed fromthe polymer composition of the present invention and have a wallthickness within the ranges noted above. It should be understood thatother parts of the camera module may also be formed from the polymercomposition of the present invention. For example, as shown, a cover mayoverly the carrier assembly 504 that includes, for example, a substrate510 (e.g., film) and/or thermal insulating cap 502. In some embodiments,the substrate 510 and/or cap 502 may also be formed from the polymercomposition.

The present invention may be better understood with reference to thefollowing examples.

Test Methods

Friction and Wear: The degree of friction generated by a sample can becharacterized by the average dynamic coefficient of friction(dimensionless) as determined according to VDA 230-206:2007 using aSSP-03 machine (Stick Slip test). Likewise, the degree of wear of asample testing may also be determined in accordance with VDA230-206:2007. More particularly, ball-shape specimens and plate shapespecimens are prepared using a polymer product via injection moldingprocess. The ball specimens is 0.5 inches in diameter. The platespecimen is obtained from middle part of ISO tensile bar by cutting twoend areas of the tensile bars. The plate specimen is fixed on sampleholder, and the ball specimen is moved in contact with the platespecimens at 150 mm/s and 15 N force. After 1000 cycles, the dynamiccoefficient of friction is obtained. The depth of wear is obtained fromball specimens by measuring diameter of worn-out ball area. Based on thediameter of the worn-out area, the depth of worn-out the ball specimenis calculated and obtained.

Melt Viscosity: The melt viscosity (Pa-s) may be determined inaccordance with ISO Test No. 11443:2005 at a shear rate of 1000 s⁻¹ andtemperature 15° C. above the melting temperature (e.g., 350° C.) using aDynisco LCR7001 capillary rheometer. The rheometer orifice (die) had adiameter of 1 mm, length of 20 mm, L/D ratio of 20.1, and an entranceangle of 180°. The diameter of the barrel was 9.55 mm+0.005 mm and thelength of the rod was 233.4 mm.

Melting Temperature: The melting temperature (“Tm”) may be determined bydifferential scanning calorimetry (“DSC”) as is known in the art. Themelting temperature is the differential scanning calorimetry (DSC) peakmelt temperature as determined by ISO Test No. 11357-2:2013. Under theDSC procedure, samples were heated and cooled at 20° C. per minute asstated in ISO Standard 10350 using DSC measurements conducted on a TAQ2000 Instrument.

Deflection Temperature Under Load (“DTUL”): The deflection under loadtemperature may be determined in accordance with ISO Test No. 75-2:2013(technically equivalent to ASTM D648-07). More particularly, a teststrip sample having a length of 80 mm, thickness of 10 mm, and width of4 mm may be subjected to an edgewise three-point bending test in whichthe specified load (maximum outer fibers stress) was 1.8 Megapascals.The specimen may be lowered into a silicone oil bath where thetemperature is raised at 2° C. per minute until it deflects 0.25 mm(0.32 mm for ISO Test No. 75-2:2013).

Tensile Modulus, Tensile Stress, and Tensile Elongation: Tensileproperties may be tested according to ISO Test No. 527:2012 (technicallyequivalent to ASTM D638-14). Modulus and strength measurements may bemade on the same test strip sample having a length of 80 mm, thicknessof 10 mm, and width of 4 mm. The testing temperature may be 23° C., andthe testing speeds may be 1 or 5 mm/min.

Flexural Modulus and Flexural Stress: Flexural properties may be testedaccording to ISO Test No. 178:2010 (technically equivalent to ASTMD790-10). This test may be performed on a 64 mm support span. Tests maybe run on the center portions of uncut ISO 3167 multi-purpose bars. Thetesting temperature may be 23° C. and the testing speed may be 2 mm/min.

Unotched and Notched Charpy Impact Strength: Charpy properties may betested according to ISO Test No. ISO 179-1:2010) (technically equivalentto ASTM D256-10, Method B). This test may be run using a Type 1 specimensize (length of 80 mm, width of 10 mm, and thickness of 4 mm). Whentesting the notched impact strength, the notch may be a Type A notch(0.25 mm base radius). Specimens may be cut from the center of amulti-purpose bar using a single tooth milling machine. The testingtemperature may be 23° C.

Rockwell Hardness: Rockwell hardness is a measure of the indentationresistance of a material and may be determined in accordance with ASTMD785-08 (Scale M). Testing is performed by first forcing a steel ballindentor into the surface of a material using a specified minor load.The load is then increased to a specified major load and decreased backto the original minor load. The Rockwell hardness is a measure of thenet increase in depth of the indentor, and is calculated by subtractingthe penetration divided by the scale division from 130.

Surface/Volume Resistivity: The surface and volume resistivity valuesare generally determined in accordance with IEC 60093 (similar to ASTMD257-07). According to this procedure, a standard specimen (e.g., 1meter cube) is placed between two electrodes. A voltage is applied forsixty (60) seconds and the resistance is measured. The surfaceresistivity is the quotient of the potential gradient (in V/m) and thecurrent per unit of electrode length (in A/m), and generally representsthe resistance to leakage current along the surface of an insulatingmaterial. Because the four (4) ends of the electrodes define a square,the lengths in the quotient cancel and surface resistivities arereported in ohms, although it is also common to see the more descriptiveunit of ohms per square. Volume resistivity is also determined as theratio of the potential gradient parallel to the current in a material tothe current density. In SI units, volume resistivity is numericallyequal to the direct-current resistance between opposite faces of aone-meter cube of the material (ohm-m).

Weldline Strength: The weldline strength may be determined by firstforming an injection molded compact camera module from a polymercomposition sample as is well known in the art. Once formed, the compactcamera module may be placed on a sample holder. The weldline of themodule may be subjected to a tensile force by a rod moving at a speed of5.08 millimeters per minute. The maximum force at break (kg_(f)) may berecorded as an estimate of the weldline strength.

Spiral Flow Length: The term “spiral flow length” generally refers tothe length reached by the flow of the composition in a spiral flowchannel (thickness of 0.3 mm) when it is injected at constant injectiontemperature and injection pressure from a central gate of a mold inwhich the spiral flow channel is formed. The spiral flow length may bedetermined in accordance with ASTM D3121-09 at a barrel temperature of230° C., molding temperature of 40° C. to 60° C., and a maximuminjection pressure of 860 bar.

Flatness Value: The flatness value (warpage) of an LGA connector samplemay be measured using an OGP Smartscope Quest 300 Optical MeasurementSystem. XYZ Measurements may be taken across the specimen starting withX and Y values corresponding to 5, 22.5, 50, 57.5 and 75 mm. Z valuesmay be normalized so that the minimum Z value corresponded to a heightof zero. The flatness value is calculated as the average of the 25normalized Z values.

Example 1

Samples 1-6 are formed from various percentages of a liquid crystallinepolymer, barium sulfate, impact modifier (Lotader® 8840), tribologicalformulation, black color masterbatch, and antistatic filler, asindicated in Table 1 below. The tribological formulation includes acombination of a high molecular weight siloxane polymer (Genioplast®Pellet S) and a fluorinated additive (Thor FPz mica). The black colormasterbatch contains 80 wt. % liquid crystalline polymer and 20 wt. %carbon black. The antistatic filler is an ionic liquid—i.e.,tri-n-butylmethylammonium bis(trifluoromethanesulfonyl)-imide (FC-4400from 3M). The liquid crystalline polymer (LCP 1) in Samples 1-4 isformed from HBA, HNA, TA, BP, and APAP, such as described in U.S. Pat.No. 5,508,374 to Lee, et al, while the liquid crystalline polymer (LCP2) in Samples 5-6 is formed from HBA, HNA, and TA. Compounding isperformed using an 18-mm single screw extruder. Parts are injectionmolded the samples into plaques (60 mm×60 mm).

TABLE 1 Sample 1 2 3 4 5 6 LCP 1 41.9 42.9 43.4 42.4 — — LCP 2 — — — —41.9 42.9 Barium Sulfate 40 40 40 40 40 40 Lotader ® 8840 1 1 1 1 1 1Black Color Masterbatch 12.5 12.5 12.5 12.5 12.5 12.5 Thor FPz Mica 2 22 2 2 2 Genioplast ® Pellet S 2 1 0.5 1.5 2 1 FC-4400 0.6 0.6 0.6 0.60.6 0.6

Samples 1-3 and 5-6 and also tested for thermal, mechanical, and wearproperties. The results are set forth below in Table 2.

TABLE 2 Sample 1 2 3 5 6 DTUL @ 1.8 Mpa (° C.) 213 209 210 190 193Charpy Notched (kJ/m²) — — — 8.6 9.3 Rockwell Hardness (M-scale) 41 4546 48 54 Tensile Strength (MPa) 101 101 101 113 116 Tensile Modulus(MPa) 6,866 6,873 7,122 7,155 7,572 Tensile Elongation (%) 3.98 4.133.43 5.30 5.03 Flexural Strength (MPa) 113 115 118 124 130 FlexuralModulus (MPa) 7,331 7,309 7,588 7,660 8,045 Dynamic Coefficient ofFriction 0.17 0.47 0.58 0.16 0.45 Wear Depth 2 157 326 2 152 WeldlineStrength (kg_(f)) — 4.46 — — — Spiral Flow Length (mm) — 29.6 — — —Warpage (mm) Before Conditioning — 0.7 — — — After Conditioning at 85°C./ — 1.1 — — — 85% RH for 72 hrs

Example 2

Samples 7-12 are formed from various percentages of a liquid crystallinepolymer, inorganic filler (barium sulfate or mica), impact modifier(Lotader® 8840), tribological formulation, and black color masterbatch,as indicated in Table 3 below. The tribological formulation includes acombination of a high molecular weight siloxane polymer (Genioplast®Pellet S) and a fluorinated additive (KT 300M PTFE). The black colormasterbatch contains 80 wt. % liquid crystalline polymer and 20 wt. %carbon black. The liquid crystalline polymer (LCP 1) in Samples 10-12 isformed from HBA, HNA, TA, BP, and APAP, such as described in U.S. Pat.No. 5,508,374 to Lee, et al, while the liquid crystalline polymer (LCP2) in Samples 7-9 is formed from HBA, HNA, and TA. Compounding isperformed using an 18-mm single screw extruder. Parts are injectionmolded the samples into plaques (60 mm×60 mm).

TABLE 3 Sample 7 8 9 10 11 12 LCP 1 — — — 36.5 40.5 50.5 LCP 2 36.5 40.550.5 — — — Barium Sulfate 40 40 — 40 40 — Lotader ® 8840 4 — 4 4 — 4Black Color Masterbatch 12.5 12.5 12.5 12.5 12.5 12.5 Mica (Suzolite) —— 26 — — 26 Genioplast ® Pellet S 5 5 5 5 5 5 PTFE (KT 300M) 2 2 2 2 2 2

Samples 7-12 are also tested for thermal, mechanical, and wearproperties. The results are set forth below in Table 4.

TABLE 4 Sample 7 8 9 10 11 12 MV 1000 (Pa-S) 116 56 96 68 33 60 MeltingTemperature (° C.) 329 329 330 328 328 329 DTUL @ 1.8 Mpa (° C.) 165 185208 200 217 234 Charpy Notched (kJ/m²) 3.7 8.8 4.0 3.9 3.8 4.4 RockwellHardness (M-scale) 22 41 30 14 34 35 Tensile Strength (MPa) 70 103 76 8393 75 Tensile Modulus (MPa) 5,900 7,725 9,599 5,687 7,476 9,133 TensileElongation (%) 2.43 3.20 1.53 3.88 2.18 1.41 Flexural Strength (MPa) 95122 117 87 115 109 Flexural Modulus (MPa) 5,749 7,441 9,493 5,569 7,2839,273 Dynamic Coefficient of Friction — 0.16 — — 0.17 — Wear Depth (μm)— 0.2 — — 1 —

These and other modifications and variations of the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention. Inaddition, it should be understood that aspects of the variousembodiments may be interchanged both in whole or in part. Furthermore,those of ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and is not intended to limit theinvention so further described in such appended claims.

1-28. (canceled)
 29. A camera module comprising a base on which ismounted a carrier assembly, wherein the base, carrier assembly, or bothcomprise a molded part, wherein the molded part contains a polymercomposition that comprises at least one thermotropic liquid crystallinepolymer and a tribological formulation, wherein the composition exhibitsa dynamic coefficient of friction of about 1.0 or less as determined inaccordance with VDA 230-206:2007.
 30. The camera module of claim 29,wherein the composition exhibits a wear depth of about 500 micrometersor less as determined in accordance with VDA 230-206:2007.
 31. Thecamera module of claim 29, wherein the tribological formulation includesa siloxane polymer having a weight average molecular weight of about100,000 grams per mole or more.
 32. The camera module of claim 31,wherein the siloxane polymer has a kinematic viscosity of about 10,000centistokes or more.
 33. The camera module of claim 29, wherein thetribological formulation further includes a fluorinated additive. 34.The camera module of claim 33, wherein the fluorinated additive includesa fluoropolymer.
 35. The camera module of claim 34, wherein thefluoropolymer is coated onto silicate particles.
 36. The camera moduleof claim 29, wherein the polymer composition further comprises inorganicfiller particles having a hardness value of about 2.5 or more based onthe Mohs hardness scale.
 37. The camera module of claim 29, wherein thepolymer composition further comprises an impact modifier.
 38. The cameramodule of claim 29, wherein the polymer composition further comprises anantistatic filler.
 39. The camera module of claim 29, wherein the liquidcrystalline polymer contains repeating units derived from terephthalicacid, isophthalic acid, 2,6-naphthalenedicarboxylic acid,4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, hydroquinone,4,4′-biphenol, acetaminophen, or a combination thereof.